The present invention relates to tubing for the extracorporal purification of the blood of a human being or of a warm-blooded animal, comprising an open loop extracorporal circulation conduit having two portions, one for extraction of the blood to be purified, the other for returning the purified blood, adapted to be connected to purification means, at least one conduit for connecting at least one of said portions to a source of a substitution solution, a bubble trap located along said loop, an evacuation conduit for the product rejected by said purification means, provided with a segment shaped to serve as a pump body adapted to be connected with a parastaltic pump and connection means to connect one to the other, removably, the respective ends of said open loop extracorporal circulation tubing to form a closed loop. This invention also relates to the use of this tubing.
This type of tubing is used particularly for persons suffering from renal insufficiency, requiring eliminating one or several harmful substances and/or to control their weight over time. The devices which exist for treating patients with renal failure are generally designed to be used by professionals in a hospital setting. In the case of chronic failure, the sick person must regularly attend, typically three times per week, a specialized hospital setting, to the detriment of his quality of life.
In the case of acute failure associated with a crisis condition and limited in time, a sick person is treated in intensive care by a non-specialized person administering this type of therapy.
The principal methods of treatment are hemodialysis, which consists in ion exchange by diffusion, between the blood and a so-called dialyzate liquid, and hemofiltration which acts by convection by mechanically filtering the blood. The two methods use an artificial membrane as a semi-permeable filter.
This treatment process comprises three phases, comprising a phase of preparing the tubing, a treatment phase properly so-called, and a process of storing the tubing. The preparation comprises two sequences which are often separate, starting the circuit which permits filling the tubing and the filter by eliminating air, and rinsing which cleans the tubing and the filter so as to carry out the treatment. After this treatment, according to whether or not it is desired to reuse the tubing, it is disinfected by leaving in the interior a disinfectant which avoids the development of bacteria, or it is emptied before discarding it.
To prepare a tubing of the state of the art so as to carry out an extracorporal purification of the blood, the end of the tubing to extract the blood is connected to a reservoir of solution and the end of this tubing for returning the blood is connected to a liquid collector. This solution is then circulated by means of the pump for extracting the blood, from the solution reservoir to the liquid collector.
This process of preparation involves several drawbacks. It requires the use of supplemental sacks which must then be eliminated while observing safety precautions. At each change, the sacks must be opened and closed. It thus involves substantial work of manipulation. Moreover, the tubing is not reusable, because of the complexity of the emptying and cleaning operations that this reuse would require.
The phases of preparation and of storage of the device are thus complicated to carry out and require a great deal of time. During treatment, the purge of the tubing and its changing of the liquid reservoir also require time and are moreover difficult to carry out by the patient himself.
There has already been proposed, particularly in U.S. Pat. No. 4,888,004, as well as in WO 90/15631, tubing comprising removable connection means between the two ends of the open loop to form a closed loop, permitting circulating a rinsing solution or to start the circuit before treatment of a patient. Although these publications relate to circuits comprising particularly a bubble trap, adapted to separate the gaseous phase from the liquid phase, none of them permits establishing a direct communication between the bubble trap and the recovery reservoir. Thus, in WO 90/15631, the conduit connecting the bubble trap to the recovery reservoir is in connection with a peristaltic pump, such that the gaseous phase cannot be freely evacuated. Eventually, it overfills, because the flow through the evacuation conduit is controlled by the peristaltic pump. In U.S. Pat. No. 4,888,004, no conduit connects the bubble trap to the recovery reservoir.
The tubing according to this invention is particularly simple to use such that it renders treatment accessible to the sick person who can care for himself at home, or in a specialized center, in the measure to which it permits reducing to the minimum any intervention in the course of the three phases of the treatment process. It thus has been designed for automatic control, or semi-automatic control of all its operating phases both before, during and after the blood purification treatment. It also thus permits being used in a hospital setting by personnel who are not specialized in this type of treatment, particularly by intensive care personnel.
Thanks to its design, this tubing can not only serve freely to evacuate the gas, but also the liquid overflow, whilst permitting detecting the undesirable presence of blood which might flow accidentally through the evacuation conduit. These advantages result in greater safety for the patient, a decrease of the risks of infection, and simplicity of use.